In numerous applications signals emitted from a signal source have to be transmitted to a microcontroller for evaluation and further processing. In that context it is already part of the prior art to transmit signals as pulse-width-modulated signals. For this it is important to monitor and assess the signal quality of a pulse-width-modulated signal. In practice sensors are known, which in addition to the actual pulse-width-modulated signal to be assessed, produce an inverted pulse-width-modulated signal such that the pulse-width-modulated signal and the inverted pulse-width-modulated signal are transmitted to a microcontroller byway of separate signal lines. By evaluating the pulse-width-modulated signal and the inverted pulse-width-modulated signal the microcontroller can then assess the signal quality of the pulse-width-modulated signal. However, the provision of an additional signal line for transmitting the inverted pulse-width-modulated signal entails greater technical equipment complexity and is therefore disadvantageous.
From DE 10 2007 030 589 A1 a method and a circuit for assessing a pulse-width-modulated signal are known, in which a signal source provides on the one hand a pulse-width-modulated signal via a first channel and on the other hand an inverted pulse-width-modulated signal via a second channel, and wherein, with the help of a differentiator and an elaborate evaluation circuit the signal quality of the pulse-width-modulated signal is assessed on the basis of the pulse-width-modulated signal and the inverted pulse-width-modulated signal.
Although it is already basically possible to assess the signal quality of a pulse-width-modulated signal in a microprocessor on the basis of the pulse-width-modulated signal and an inverted pulse-width-modulated signal provided via a separate signal line, there is a need to simplify the assessment of the signal quality of a pulse-width-modulated signal, in particular in order to reduce the technical equipment complexity.